New Tamron 28-75 vrs. Nikon 28-70

I have been working with the new Tamron 28-75 2.8 for 3 weeks now. It is an exceptional lens. I've tested against many other good zooms and this Tamron is clearly a winner. The one I haven't tested it against is the Nikon 28-70 2.8 because I don't have one to test. I would be very surprised if the Nikon was as good. The Tamron actually holds it's on very well against really good single focal length lenses like the 50 1.8. Another plus is the Tamron is very compact for a 2.8 and flare is well controlled for a zoom. Don't hesitate just buy it!
Best regards,
Steve